I did a playfield swap for my Eight Ball Deluxe.

Now, it appears several coils are not firing, and others are firing instead.

To narrow down the root of the problem, I replaced the solenoid driver board with one that works 100%.  Made no difference.

Than I replaced the MPU with my Alltek.  That made no difference either.

The problem occurs during normal play and during the coil test mode.

It is not as simple as my mixing up wires on the playfield.  I left coils wired when I did the swap.

I guess I should check out the J4 connectors.  Is there anything else it could be ?


Dunk-a-shane

Is the issue with wrong switches being detected, or the wrong coils being fired ?

e.g. go into solenoid test. Are the proper solenoids firing (compare with the manual).
Then, go in switch test and confirm if the switches are properly detected (again, check the manual).

There appears to be a short or miswiring perhaps?

Were the pesky 0.05 uF disc caps across the switches ever replaced?
They often cause intermittent or permanent switch 'detection' when bad.

...Trying to help you identify if the issue is on the switch matrix or solenoids...


Cheers,
- Sylvain.

I haven't run the switch test, but there are 2 or 3 coils that fire twice, while 2 or 3 others do not fire at all.

I did discover something.  When I run the lamp test, the expander board relay does not click on and off like usual.  When I checked the schemativs, the 3 coils that are not firing are run by the expander board.  And the three coils that fire twice are the ones that are teamed with the expander board coils that aren't firing.  

So, it looks like the sol. exp. board relay ( or some other part of the board ) is not working, and as a result, when the last 3 coils go to fire, their counterparts fire instead.  Does that seem reasonable ?  

Good additional details.
Yes, you probably have found the area of the issue.

Check Clay's pointers here:
http://www.pinrepair.com/bally/index3.htm#expand

Cheers,
- Sylvain.

Thanks Sylvain.

I'm going to go at it tonight with a renewed sense of determination ( and desperation ) !

I'll trade you that old lump for a working Galaxy?

Well, just for kicks, I put in the expander board from my Fathom into the Eight Ball Deluxe and it still doesn't work.  Meanwhile, the expander board from my EBD works fine in the Fathom, so it must be an issue that is related to the board, yet is not the board itself.

Any advice on what to investigate next ?


P.S.  Nice try Ottogd, but I already bought a crappy looking Galaxy from some loser.

Maybe, check the transistor related to the expander board on the solenoid driver board.

*wires*

ping them from a to b making sure you don't end up at c instead

Thanks "Hal & hide"... I am presently going through the schematics now and tracing what goes where.  I assumed the Sol exp board was run by a transistor on the lamp board, but is it possible that the transistor is actually on the AUX. lamp board ?  I don't see anything on the lamp schematic that indicates a transistor that that controls the  sol exp board.

Mr Niceguy, did you read the link Sylvain sent you? There was something about the expander board multiplexing switches using a lamp socket as the A/B switch. Seems kinda back assward but I guess it was done to meet budget.

The transistor for the solenoid expander board is on the ''solenoid driver board'' for my Centaur. Transistor Q11

1- Does the relay click during Lamp Test ? It should.
Make sure there are no cold solder joints under the header pins
and relay of the Solenoid Expander board. Bally machines of that era
are notorious for cold solder joints at connector headers, on all boards...

2- Looking at the EBD Schematics, you need four things to operate the
relay on the Solenoid Expander board:
- presence of 43V solenoid voltage going to one side of the relay coil
    on the board (pin 9);
- trigger from the lamp driver, feeding the bulb as well as the opto (pin 2);
- presence of the switched lamp voltage (pin 1);
- and presence of the mandatory ground (pin 3).

3- if I read the schematics correctly, the trigger originates from the main
   lamp driver board, J3 pin 11 (Q54). There seems to be a mistake on
   the schematics, J3 pin 11 of the lamp driver should connect to J1-2 of
   the Solenoid Expander board (and not J1-3 as printed in the diagram).

Checking the above, using the pinrepair.com reference, taking continuity
and/or voltage measurements, should easily get you back in business.

Cheers,
- Sylvain.

Thanks Sylvain.  

I reflowed the solder at the header pins. However, I ended up swapping with a fully functional board anyway and it still didn't work.  You're right...I'll just have to start checking voltages and trace back the problem.   I made a little progress, then got sidetracked.  I hope it's just a transistor on the lamp board and not a rectifier issue.  

I'll give it another go tomorrow.

Update :

Rather than track down the transistor on the Lamp board that may have been fried, I put in another lamp board that I knew was 100 %.  ( From the schematic, I believe Q54 goes to the solenoid expander relay, but I never confirmed it ).   When I swapped the lamp boards, the relay came back on line.  

Now when I run the coil test, the relay pulls in and the ball kicker and the saucer coils fire, BUT the 4-target reset coil still does not fire.

When I check the lugs, I get around 55 volts.   Just for fun, I put in a comparable coil, but it didn't fire either.  

Can't be a transistor on the SDB because the same transistor fires the #2 drop target and that coil works fine.  

I'm kinda lost as to how to go from here.  I appear to have continuity, proper voltage and good transistors but still have no coil action for that 4-target bank.

I replaced BR1 with a bigger rectifier, but TP4 is still only measuring 5.5 VAC rather than 6.5 VAC.  Could that be an issue ?  If so, why would it be so low and how do I beef it up ?

So many questions....so little hope.

Getting there!

In order to fire a solenoid, you need +54V or so on one lug
(it is present all the time on all coils providing that both
main solenoid & under playfield fuses and holders are good),
and connection to ground on the other lug (via the drive transistor
on the solenoid driver/solenoid expander relay contact).

You will need to trace the ground side wire of that 4-target bank
reset coil, all the way to/through the solenoid expander.
There is probably a missing or misconnected wire somewhere.

Unfortunately I cannot help you any further here. All the details
are in the above posts/replies and schematics. Yes, Q54 too

Do not give-up, you can do it !

Good Luck !
- Sylvain.

Quoted from sylvain

Getting there!

In order to fire a solenoid, you need +54V or so on one lug
(it is present all the time on all coils providing that both
main solenoid & under playfield fuses and holders are good),
and connection to ground on the other lug (via the drive transistor
on the solenoid driver/solenoid expander relay contact).

You will need to trace the ground side wire of that 4-target bank
reset coil, all the way to/through the solenoid expander.
There is probably a missing or misconnected wire somewhere.

Unfortunately I cannot help you any further here. All the details
are in the above posts/replies and schematics. Yes, Q54 too

Do not give-up, you can do it !

Good Luck !
- Sylvain.

"... A-hunting I will go, a-hunting I will go......"   

Thanks Sylvain.  Next time I post it will be to tell great tales of my success !

Quoted from sylvain

You will need to trace the ground side wire of that 4-target bank
reset coil, all the way to/through the solenoid expander.
There is probably a missing or misconnected wire somewhere.

Unfortunately I cannot help you any further here. All the details
are in the above posts/replies and schematics. Yes, Q54 too

Do not give-up, you can do it !

Good Luck !
- Sylvain.

ALL HAIL THE MIGHTY SYLVAIN !!  

Finally had enough.  Started cutting off wire ties and tracing the wires back from the offending coil's lugs.  Only had to go about 12 inches to find the problem.  The power wire to the coil was daisy chained from the saucer coil.  At first glance, it appeared to be making decent contact.  Then i gave it a slight pull and it came right off !  I'm both estatic and angry at the same time !  

The biggest enemy to trouble-shooting any electrical or mechanical problem is when 2 things happen at the same time but are completely unrelated !   Since my lamp board transistor that drove the relay was fried, I assumed that it had to be the root cause of my target reset problem.  Never occurred to me to bother looking for a power issue as well.

I was just about to put my EBD up for sale for $500 to any MAACA member.  But thanks to Sylvain, I didn't.      

( Oops...maybe I shouldn't have said that. )

EBD for 500$, hey remember, non-working feature on those early 80's are always much more easy to fix then we think. Only follow the logical step and you find the problem. Very often it's a problem from bad contact or damage wires because of rust or a transistor very easy to change.